This application claims the benefit of Korean Application No. 2001-60981, filed Sep. 29, 2001, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a paper feeding apparatus and method of use in a printer, and more particularly, to a paper feeding apparatus and method capable of printing images on both sides of a sheet of paper by improving a feeding path of the sheet of paper.
2. Description of the Related Art
Referring to FIG. 1, in a conventional printer, a paper supplying cassette 11 in which paper is stacked is installed at the bottom of a main body 10. The paper in the cassette 11 is picked-up, sheet by sheet, by a pick-up roller 12. The picked-up sheet is transferred along a predetermined feeding path P1 to a developing section 15 by a feeding roller 13. The developing section 15 comprises an electrification roller 17, a photosensitive roller 16, a developing roller 18 and a transfer roller 19. The photosensitive roller 17 is electrified to a desired electric potential by the electrification roller 16, and electrostatic latent images, which correspond to the desired images, are formed on the electrified surface by a laser scan unit 20. Toner supplied by the developing roller 18 is transferred to the electrostatic latent area. The formed toner image is transferred and printed to a sheet moving between the photosensitive roller 17 and the transfer roller 19.
The image printed on the sheet is fixed at a high temperature while passing through a fixing section 21, and the sheet is ejected along an ejecting path P2 to the exterior of the main body 10 by an ejecting roller 22.
In the case of duplex printing, the sheet, on one side of which an image is printed, is fed along the ejecting path P2 such that a trailing end is held by the ejecting roller 22. The sheet is then fed along a reversing path P3 by counter rotation of the ejecting roller 22. There is a guide member 23 to guide the feed direction of the sheet between the ejecting path P2 and the reversing path P3.
The sheet delivered to the reversing path P3 is again fed along the feeding path P1 by the pick-up roller 12 and the feeding roller 13, to the developing section 15, where an image is printed on the other side of the sheet. Further, the duplex printed sheet is ejected through the fixing section 21 and the ejecting path P2 to the exterior of the main body 10.
In the conventional printer in the case of duplex printing, the first sheet is fed along the feeding path P1 and an image is formed on one side thereof at the developing section 15. Subsequently, it is again fed along the ejecting path P2, the reversing path P3 and the feeding path P1 to the developing section 15 to print an image on the other side thereof. Therefore, it takes a relatively long time to print images on both sides of the sheet, resulting in low printing speed.
In order to solve the above problems, shortening the feeding path of the sheet has been considered, however, this method causes the sheet to be heated at a high temperature by the fixing section 21. This causes the surface temperature of the photosensitive roller 17 to increase, thereby affecting the toner, which is sensitive to temperature. Thus, the function of the toner is adversely affected.
Accordingly, it is an object of the present invention to provide a paper feeding apparatus and method of use in a printer, which is capable of increasing the efficiency printing.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The foregoing and other objects of the present invention are achieved by providing a paper feeding apparatus for use in a printer, including a sheet feeding path between a sheet feeding section and a developing section; a sheet ejecting path disposed such that a plurality of sheets on which an image is printed at the developing section is fed to the sheet ejecting path via a fixing section and an ejecting roller; a reversing path to feed the sheets from the sheet ejecting path to the sheet feeding path; a reversing tray disposed between the sheet ejecting path and the reversing path to feed the sheets from the reversing path to the sheet feeding path; and a guide member rotatably mounted between the sheet ejecting path and the reversing tray, to direct the sheets to the sheet ejecting path or the reversing tray and to guide the sheet from the reversing tray to the reversing path.
The foregoing and other objects of the present invention are also achieved by providing a paper feeding method to duplex print in a printer, the method including: sequentially feeding a plurality of sheets including an nth paper unit from a sheet supplying section to a developing section; printing images at the development section on a first side of the sheets including the nth paper unit; sequentially reversing the printed sheets; feeding the reversed sheets to the developing section at an interval; feeding sheets including an n+1th paper unit, interposed between adjacent ones of the reversed sheets of the nth paper unit; and printing images at the development section on a second side of the sheets including the nth paper unit and ejecting the printed sheets, to an exterior of the printer.